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bioRxiv2018

Status of urban feral cats Felis catus in England: A comparative study

This study sought to determine whether a change in the abundance of feral cats (Felis catus) in three areas of England had occurred between the completion of a survey undertaken by the Ministry for Agriculture Fisheries and Food in 1986/7 and the turn of the century. In the event of a rabies outbreak occurring in Britain, feral cats would be one vector of the disease that would need to be controlled under the Rabies (control) Order 1974. A total of 741 \"high risk sites\", found to provide appropriate conditions for feral cats, were surveyed between 1999 and 2000. The total number of feral cat colonies located within the survey areas was found to have fallen by 37% from 68 in 1986 to 43 in 1999/2000, translating to an estimated 212-247 fewer individual feral cats. Factories/trading estates and industrial premises continued to be the most common sites associated with urban feral cat colonies. However, the closing down of many traditional industries, such as mills and dockyards, and their replacement by more secure and insulated modern buildings, less amenable to feral cats finding warmth and food, had assisted the observed fall in numbers along with the effectiveness of neutering programs which are now taking place on many sites. Through this study information regarding feral cat colonies in urban landscapes as well colony size was gathered and fed into rabies contingency plans to help keep Britain rabies free into the future.

zoology↗

bioRxiv2018

Adaptation of artificial diets for Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) at laboratory rearing

Helicoverpa armigera is an important pest of crops worldwide, and several studies have focused on the development of artificial diets for this species. However, studies evaluating the insect{acute}s performance at nutritionally different diets are scarce. Larval development is dependent on the ratio of protein and carbohydrates. The aim of this study was to evaluate the biology and to compare the consumption and use of food of H. armigera larvae on diets with different protein levels. The nutritional index, the relative consumption rate, the relative metabolic rate, the relative growth rate, and the apparent digestibility were higher in the diet with added protein. On the other hand, the conversion efficiency of digested food was lower, resulting in a higher metabolic cost. In terms of biological aspects, larval survival was higher for the diet with average protein content and lower for the diet with a high protein level. The pupal period was longer for the diet with a higher protein content, while pupal survival was lower. Among the evaluated diets, the diet with an average protein content resulted in a higher net reproductive rate, a shorter time for the population to double in number, and the highest rates of population growth. The results suggest that lower or higher protein contents in the diets of H. armigera negatively affect the biological aspects of this species.

zoology↗

bioRxiv2018

Sexual conflict in self-fertile hermaphrodites: reproductive differences among species, and between individuals versus cohorts, in the leech genus Helobdella (Lophotrochozoa; Annelida; Clitellata; Hirudinida; Glossiphoniidae)

Leeches and oligochaetes comprise a monophyletic group of annelids, the Clitellata, whose reproduction is characterized by simultaneous hermaphroditism. While most clitellate species reproduce by cross-fertilization, self-fertilization has been described within the speciose genus Helobdella. Here we document the reproductive life histories and reproductive capacities for three other Helobdella species. Under laboratory conditions, both H. robusta and H. octatestisaca exhibit uniparental reproduction, apparently reflecting self-fertility, and suggesting that this trait is ancestral for the genus. However, the third species, H. austinensis, seems incapable of reproduction by self-fertilization, so we inferred its reproductive life history by analyzing reproduction in breeding cohorts. Comparing the reproductive parameters for H. robusta reproducing in isolation and in cohorts revealed that reproduction in cohorts is dramatically delayed with respect to that of isolated individuals, and that cohorts of leeches coordinate their cocoon deposition in a manner that is not predicted from the reproductive parameters of individuals reproducing in isolation. Finally, our comparisons of reproductive capacity for individuals versus cohorts for H. robusta, and between different sizes of cohorts for H. austinensis, reveal differences in resource allocation between male and female reproductive roles that are consistent with evolutionary theory.

zoology↗

bioRxiv2018

Following the dung or the climate? Species richness pattern of dung beetles (Scarabaeinae) on the Americas

AbstractClimatic conditions are a main driver of species richness. Specifically, increase on climatic instability may reduce species richness directly and indirectly by reducing resources available. This hypothesis is evaluated here using a producer- consumer interaction to explain dung beetle richness on a continental scale (America) using mammal richness as resource proxy and temperature and precipitation seasonality as proxy for climatic instability. A spatial path analysis was built in order to evaluate this hypothesis while controlling for spatial autocorrelation and differences on the sampling effort and abundance of each study (n=115) gathered from the literature. Dung beetle richness was directly explained by temperature seasonality, precipitation seasonality and mammal richness, whereas only precipitation seasonality had an effect modulated by mammal richness. This result reinforces the notion that species richness can be explained by climatic conditions, but also reveals the importance of biotic interactions in order to understand the mechanisms behind such patterns.

zoology↗

bioRxiv2018

The flower flies and the unknown diversity of Drosophilidae (Diptera): a biodiversity inventory in the Brazilian fauna

Diptera is a megadiverse order, reaching its peak of diversity in Neotropics, although our knowledge of dipteran fauna of this region is grossly deficient. This applies even for the most studied families, as Drosophilidae. Despite its position of evidence, most aspects of the biology of these insects are still poorly understood, especially those linked to natural communities. Field studies on drosophilids are highly biased to fruit-breeders species. Flower-breeding drosophilids, however, are worldwide distributed, especially in tropical regions, although being mostly neglected. The present paper shows results of a biodiversity inventory of flower-breeding drosophilids carried out in several localities in Brazil, based on samples of 125 plant species, from 47 families. Drosophilids were found in flowers of 56 plant species, from 18 families. The fauna discovered showed to be highly unknown, comprising 28 species, 12 of them (>40%) still undescribed. Not taking in account opportunist species, two thirds of the diversity exclusive from flowers were undescribed. The Drosophila bromeliae species group was the most representative taxon, with eight species (six undescribed), including four polyphagous and four Solanum-specialised species. This specialisation on Solanum is reported for the first time for Drosophila. Other taxa of restrict flower-breeding drosophilids were the Drosophila lutzii species group and the genus Zygothrica. Some specimens of the genera Cladochaeta, Rhinoleucophenga and Scaptomyza were found, but their relations to flowers are unclear. Additionally, ten species of ample niche was found using flowers opportunistically. Localities and host plants are recorded for all species collected.

zoology↗

bioRxiv2018

Evaluation of rearing parameters of a self-limiting strain of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae)

The Mediterranean fruit fly, Ceratitis capitata, (medfly) is an important pest of stone and pome fruit, causing significant economic losses worldwide. Current control is primarily based on insecticides, often mixed with protein baits. Chemical approaches are effective but there are label limits to avoid residues in fruits and harm to the environment and sustained use will lead to pesticide resistance in the medfly pest. In recent years, emphasis has been placed on environmentally friendly methods to control medfly.\n\nOxitec has developed a self-limiting medfly strain (OX3864A) that demonstrates conditional female-specific mortality in the early life stages. Sustained release of OX3864A males offers a mating-based approach to medfly control, which should lead to significant economic benefits in area-wide programmes. Furthermore, a heritable fluorescent marker provides quick and accurate identification of released OX3864A males for efficient monitoring in the field.\n\nAn important prerequisite of mating-based control programmes is the availability of adequate numbers of high-quality male flies in a sustainable and cost-effective manner. This paper summarises rearing optimisations for the OX3864A strain and the production of OX3864A males.

zoology↗

bioRxiv2018

Heterochrony of puberty in the European Badger (Meles meles) can be explained by growth rate and group-size: Evidence for two endocrinological phenotypes

Puberty is a key stage in mammalian ontogeny, involving endocrinological, physiological and behavioural changes, moderated by intrinsic and extrinsic factors. Thus, not all individuals within one population achieve sexual maturity simultaneously. Here, using the European badger (Meles meles) as a model, we describe male testosterone and female oestrone profiles (using Enzyme-immunoassays) from first capture (3 months, post-weaning) until 28 months (attaining sexual maturity and final body size), along with metrics of somatic growth, scent gland development and maturation of external reproductive organs as well as intra-specific competition. In both sexes, endocrinological puberty commenced at ca. 11 months. Thereafter, cub hormone levels followed adult seasonal hormone patterns but at lower levels, with the majority of cubs reaching sexual maturity during their second mating season (22-28 months). Interestingly, there was evidence for two endocrinological phenotypes among male cubs (less evident in females), with early developers reaching sexual maturity at 11 months (first mating season) and late developers reaching sexual maturity at 22-26 months (second mating season). Early developers also attained a greater proportion of their ultimate adult size by 11 months, exhibiting faster growth rates than late developers (despite having similar adult size). Male cubs born into larger social groups tended to follow the late developer phenotype. Our results support the hypothesis that a minimum body size is required to reach sexual maturity, which may be achieved at different ages, even within a single population, where early maturity can confer individual fitness advantages and enhance population growth rate.

zoology↗

bioRxiv2018

Chemical blueprints to identifying fire ants: overview on venom alkaloids

Solenopsis fire ants are remarkably difficult to identify using morphological characters, particularly from the most abundant minor workers. The present manuscript introduces a set of chemical tools to facilitate species diagnosis from field-collected fire ant samples, herein focusing on minor workers. Fire ants from different localities (native and invaded) were analysed using gas-chromatography. Samples were collected from the field into organic solvents; sampling effort included 14 species, and a suspected hybrid. A total of 32 piperidine alkaloids were spotted and tentatively identified and representative relative chemical proportions for minor workers are presented for the first time for a number of species. It is hoped that the provided info will prove useful to researchers working on fire ants in future studies. Further compounds are being analysed for additional auxiliary tools.

zoology↗

bioRxiv2018

Sustained hovering, head stabilization and vision through the water surface in the Pied kingfisher (Ceryle rudis).

Pied kingfishers (Ceryle rudis) capture fish by plunge diving from hovering that may last several minutes. Hovering is the most energy-consuming mode of flight and depends on active wing flapping and facing headwind. The power for hovering is mass dependent increasing as the cube of the size, while aerodynamic forces increase only quadratically with size. Consequently, birds above a certain body mass can hover only with headwind and for very short durations. Hummingbirds are referred to as the only birds capable of hovering without wind (sustained hovering) due to their small size (ca. 2-20 gr), high wing-beat frequency and unique anatomy.\n\nWe studied the hovering characteristics of pied kingfishers in relation to wind and sun orientation, in 139 hovers. Furthermore, plunge diving necessitates the coping with the visual effects of light at the air/water interface. The kingfishers oriented their body axis towards the wind more than towards the sun. Hovering in little or no wind was common. With increased wind speed (a) orientation precision increased, (b) wing beat amplitude did not change, (c) wing beat frequency decreased and (d) body tilt became more horizontal. The head was highly stabilized and with orientations that indicated monocular viewing of prey.\n\nWe conclude that pied kingfishers achieve sustained hovering. This is despite their being significantly heavier than the theoretical maximum and showing ordinary kinematics and morphology. Head stabilization is a means of aiding viewing of submerged prey across the interface.

zoology↗

bioRxiv2018

How will changes in local climate affect hawksbill hatchling production in Brazil?

Local climatic conditions can influence sea turtle embryonic development and hatchling viability. Therefore, it is crucial to understand these influences as well as potential ramifications to population stability under future climate change. Here, we examined the influences of five climatic variables (air temperature, accumulated and average precipitation, humidity, solar radiation, and wind speed) at different temporal scales on hawksbill sea turtle (Eretmochelys imbricata) hatchling production at ten nesting beaches within two regions of Brazil (five nesting beaches in Rio Grande do Norte and five in Bahia). Air temperature and accumulated precipitation were the main climatic drivers of hawksbill hatching success across Brazil and in Rio Grande do Norte, while air temperature and average precipitation were the main climatic drivers of hatching success at Bahia. Solar radiation was the main climatic driver of emergence rate at both regions. Conservative and extreme climate scenarios show air temperatures are projected to increase, while precipitation projections vary between scenarios and regions throughout the 21st century. We predicted hatching success of undisturbed nests (no recorded depredation or storm-related impacts) will decrease in Brazil by 2100. This study shows the determining effects of different climate variables and their combinations on an important and critically endangered marine species.

zoology↗

bioRxiv2018

Combined effects of migration distance, foraging method vegetation density, and population density on wing shapes of boreal songbirds

In birds, migration distance is known to influence morphological attributes that influence flight performance, especially wing shape. However, wing shape is under the likely influence of less documented factors such as foraging method, vegetation density and isolation of individuals and populations. To better understand factors leading to interspecific differences in wing shape, we measured the pointedness of wings (Kipps distance) of 1017 live birds of 22 species in an eastern Canadian boreal forest. We modeled wing pointedness as a function of migration distances from eBird records, foraging, habitat, and population density data from Birds of North America monographs. Long-distance migrants and species living in low-density vegetation had more pointed wings than shorter-distance migrants and dense-vegetation dwellers, in accordance to our predictions. After accounting for vegetation density and migration distance, we found no link between the extent of aerial foraging or mean breeding population density, an indicator of isolation, and wing pointedness. Those results are consistent with a tradeoff between sustained flight efficiency and maneuverability, but suggest that interspecific variation in wing shape due specifically to foraging method or habitat isolation is nonexistent or obscured by other factors.

zoology↗

bioRxiv2018

Freshwater Adaptation at the Molecular Scale in the Unique Sponges of Lake Baikal

Freshwater sponges (Spongillida) are a unique lineage of demosponges that secondarily colonized lakes and rivers and are now found ubiquitously in these ecosystems. They developed specific adaptations to freshwater systems, including the ability to survive extreme thermal ranges, long-lasting dessication, anoxia, and resistance to a variety of pollutants. While spongillids have colonized all freshwater systems, the family Lubomirskiidae is endemic to Lake Baikal, and plays a range of key roles in this ecosystem. Our work compares the genomic content and microbiome of individuals of three species of the Lubomirskiidae, providing hypotheses for how molecular evolution has allowed them to adapt to their unique environments. We have sequenced deep (>92% of the metazoan Benchmarking Universal Single-Copy Orthologs (BUSCO) set) transcriptomes from three species of Lubomirskiidae and a draft genome resource for Lubomirskia baikalensis. We note Baikal sponges contain unicellular algal and bacterial symbionts, as well as the dinoflagellate Gyrodinium. We investigated molecular evolution, gene duplication and novelty in freshwater sponges compared to marine lineages. Sixty one orthogroups have consilient evidence of positive selection. Transporters (e.g. zinc transporter-2), transcription factors (aristaless-related homeobox) and structural proteins (for example actin-3), alongside other genes, are under strong evolutionary pressure in freshwater, with duplication driving novelty across the Spongillida, but especially in the Lubomirskiidae. This addition to knowledge of freshwater sponge genetics provides a range of tools for understanding the molecular biology and, in the future, the ecology (for example, colonization and migration patterns) of these key species.

zoology↗

bioRxiv2018

Effects of exposure to sublethal concentrations of methoxyfenozide on honey bee colony activity and thermoregulation

Methoxyfenozide is an insect growth regulator (IGR) commonly used in agricultural to simultaneously control pests and preserve beneficial insect populations; however, its impact on honey bees in not fully understood. We conducted field and laboratory experiments to investigate bee health in response to field-relevant doses of this pesticide. Significant effects were observed in honey bee colony flight activity and thermoregulation after being treated with methoxyfenozide. Data collected indicated that hives fed 500 ppb methoxyfenozide treated pollen patty had: 1) a significantly reduced rate of daily hive weight loss due to forager departure at the start of the colonys daily activity; 2) the end of the colonys daily activity delayed by 17-21 minutes compared to Control; and 3) higher temperature variability during the winter. Colonies in the 125 ppb treatment group had fewer differences with the Control group, but did show a delay in the foraging end time by 30-46 minutes compared to the Control. Bee colony metrics of adult bee mass and brood surface area, and individual bee measurements of head weight, newly-emerged bee weight, and hypopharyngeal gland size were not significantly affected by the methoxyfenozide exposure levels of our experiments. An experiment conducted using the same treatment groups in the spring resulted in fewer differences among groups than did the experiments conducted in the fall. Analyses of methoxyfenozide concentrations in the treatment patty, wax, and bee bread showed that: 1) observed methoxyfenozide concentrations were about 18-60% lower than the calculated concentrations; 2) no residues were observed in wax in any treatment; and 3) methoxyfenozide was detected in stored bee bread in the 500 ppb treatment, at concentrations about 1-2.5% of the observed concentration for that treatment. These results suggest that there may be significant effects on honey bee colony behavior (and possibly health) in the field that are difficult to detect through traditional hive inspections and individual metrics.

zoology↗

bioRxiv2018

Distribution of duck-origin parvovirus in Cherry Valley ducks in vivo over time and histopathological investigation

In 2015, we successfully isolated a strain of duck-origin parvovirus from Cherry Valley ducks, which we named QH-L01. In this study, duck-origin parvovirus in Cherry Valley ducks was quantified and localized by quantitative real-time PCR (qPCR) and immunohistochemistry (IHC), and pathological damage to the tissues and organs was observed by hematoxylin-eosin staining (HE staining). qPCR showed that the viral load was higher in the spleen, brain, lung, cecum, ileum, and duodenum over time. The results from IHC experiments showed positive reactions in hepatocytes, epithelium of the lung atrium, myocardial cells, goblet cells of the intestine, and brain cells. Primary histological examination revealed pulmonary lobule depletion and dilation in the lung as well as necrosis and erosion of the villus tips in the duodenum, ileum and cecum. This study is the first demonstration that duck-origin parvovirus can be transmitted from the spleen to the brain and lung, resulting in proliferation and dissemination of the virus to the cecum, ileum, duodenum and other tissues through the blood. The lung, duodenum, ileum and cecum may thus represent the main target tissues and organs for duck-origin parvovirus.

zoology↗

bioRxiv2018

Recruit symbiosis establishment and Symbiodiniceae composition influenced by adult corals and reef sediment

For most reef-building corals, the establishment of symbiosis occurs via horizontal transmission, where juvenile coral recruits acquire their algal symbionts (family Symbiodiniaceae) from their surrounding environment post-settlement. This transmission strategy allows corals to interact with a diverse array of symbionts, potentially facilitating adaptation to the newly settled environment. We exposed aposymbiotic Pseudodiploria strigosa recruits from the Flower Garden Banks to natal reef sediment (C-S+), symbiotic adult coral fragments (C+S-), sediment and coral fragments (C+S+), or seawater controls (C-S-) and quantified rates of symbiont uptake and Symbiodiniaceae community composition within each recruit using metabarcoding of the ITS2 locus. The most rapid uptake was observed in C+S+ treatments and this combination also led to the highest symbiont alpha diversity in recruits. While C-S+ treatments exhibited the next highest uptake rate, only one individual recruit successfully established symbiosis in the C+S-treatment, suggesting that sediment both serves as a direct symbiont source for coral recruits and promotes (or, potentially, mediates) transmission from adult coral colonies. In turn, presence of adult corals facilitated uptake from the sediment, perhaps via chemical signaling. Taken together, our results reinforce the key role of sediment in algal symbiont uptake by P. strigosa recruits and suggest that sediment plays a necessary, but perhaps not sufficient, role in the life cycle of the algal Symbiodinaceae symbionts.

zoology↗

bioRxiv2018

High rates of apoptosis visualized in the symbiont-bearing gills of deep-sea Bathymodiolus mussels

Symbiosis between Bathymodiolus and Gammaproteobacteria enables these deep-sea mussels to live in toxic environments like hydrothermal vents and cold seeps. The quantity of endosymbionts within the gill-bacteriocytes appears to vary according to the hosts environment. We investigated the hypothesis of a control of the endosymbionts density by apoptosis, a programmed cell death. We used fluorometric TUNEL-method and active Caspase-3-targeting antibodies to visualize and quantify apoptotic cells in mussel gills. To avoid artefacts due to depressurization upon specimen recovery from the deep-sea, we compared the apoptotic rates between mussels recovered unpressurised, versus mussels recovered in a pressure-maintaining device, in two species from hydrothermal vents on the Mid-Atlantic Ridge: Bathymodiolus azoricus and B. puteoserpentis. Our results show that pressurized recovery had no significant effect on the apoptotic rate in the gill filaments. Apoptotic levels were highest in the ciliated zone and in the circulating hemocytes, compared to the bacteriocyte zone. Apoptotic gill-cells in B. aff. boomerang from the pockmarks off the Gulf of Guinea, show similar distribution patterns. Deep-sea symbiotic mussels have much higher rates of apoptosis in their gills than the coastal mussel Mytilus edulis without chemolithoautotrophic symbionts. We discuss how apoptosis might be one of the mechanisms that contribute to the adaptation of deep-sea mussels to toxic environments and/or to symbiosis.

zoology↗

bioRxiv2018

Speciation in a biodiversity hotspot: phylogenetic relationships, species delimitation, and divergence times of the Patagonian ground frogs of Eupsophus roseus group (Alsodidae)

The alsodid ground frogs genus Eupsophus is divided into the roseus (2n=30) and vertebralis (2n=28) groups, distributed throughout the temperate Nothofagus forests of South America. Currently, the roseus group is composed by four species, while the vertebralis group consists of two. Phylogenetic relationships and species delimitation within each group are controversial. In fact, previous analyses considered that roseus group was composed between four to nine species. In this work, we evaluated phylogenetic relationships, diversification times, and species delimitation within roseus group using a multi-locus dataset. For this purpose, mitochondrial (D-loop, Cyt b, and COI) and nuclear (POMC and CRYBA1) partial sequences, were amplified from 164 individuals, representing all species. Maximum Likelihood (ML) and Bayesian approaches were used to reconstruct phylogenetic relationships. Species tree was estimated using BEAST and singular value decomposition scores for species quartets (SVDquartets). Species limits were evaluated with six coalescent approaches. Diversification times were estimated using mitochondrial and nuclear rates with LogNormal relaxed clock in BEAST. Nine well-supported monophyletic lineages were recovered in Bayesian, ML, and SVDquartets, including eight named species and a lineage composed by specimens from Villarrica population (Bootstrap: >90, PP:> 0.9). Single-locus species delimitation analyses overestimated the species number in E. migueli, E. calcaratus and E. roseus lineages, while multi-locus analyses recovered as species the nine lineages observed in phylogenetic analyses (>0.95). It is hypothesized that Eupsophus diversification occurred during Mid-Pleistocene (0.42-0.14 Mya), with most species originated after of the Last Southern Patagonian Glaciation (0.18 Mya). Our results revitalize the hypothesis that E. roseus group is composed by eight species and support to Villarrica lineage as a new putative species.

zoology↗

bioRxiv2018

Conserved patterns of alternative splicing in response to cold acclimation in fish

Phenotypic plasticity is an important aspect of an organisms response to environmental change that often requires the modulation of gene expression. These changes in gene expression can be quantitative as a result of increases or decreases in the amounts of specific transcripts, or qualitative as a result of the expression of alternative transcripts from the same gene (e.g., via alternative splicing of pre-mRNAs). Although the role of quantitative changes in gene expression in phenotypic plasticity is well known, relatively few studies have examined the role of qualitative changes. Here, we use skeletal muscle RNA-seq data from Atlantic killifish (Fundulus heteroclitus), threespine stickleback (Gasterosteus aculeatus) and zebrafish (Danio rerio) to investigate the extent of qualitative changes in gene expression in response to cold. Fewer genes demonstrated alternative splicing than differential expression as a result of cold acclimation; however, differences in splicing were detected for between 426 and 866 genes depending on species, indicating that large numbers of qualitative changes in gene expression are associated with cold acclimation. Many of these alternatively spliced genes were also differentially expressed, and there was functional enrichment for involvement in muscle contraction among the genes demonstrating qualitative changes in response to cold acclimation. Additionally, there was a common group of 29 genes with cold-acclimation-mediated changes in splicing in all three species, suggesting that there may be a conserved set of genes with expression patterns that respond qualitatively to prolonged cold temperatures across fishes.\n\nSummary statementQualitative changes in gene expression, such as those mediated by alternative splicing of mRNAs, are involved in phenotypic plasticity in response to prolonged cold acclimation in ectothermic animals

zoology↗